Rib Micro wire (brown nickel, from Flybox); 5-6lb mono, black wire or silver wire also work
Body Chuck and Duck hare and squirrel dubbing, black
Hackle Old Indian or Chinese hackle
How to tie it
Put a size 12 Fario barbless dry fly hook in the vise and start black thread.
Dub the body onto the thread, building it up at the thorax.
Spiral the micro wire rib forward in the opposite direction to make a segmented body, tie it off at the head and break it off.
Brush out the dubbing before adding the hackle so it looks buggier and traps air to help it float.
Wax the thread, tie in a suitable hackle, and pull the stem back until it cracks so it wraps neatly.
Sweep all the fibres back and take a couple of turns, then tie off.
Add varnish to the thread, whip finish, brush the body back, and varnish the head.
Other versions
4 more in the app: Basic Black Bob's Bits - as tied by Alun Rees Fly Fishing, Claret ribbed Bob's Bits - consensus of Tim Joyce and Davie McPhail, Claret Bob's Bits with white hackle-fibre wing - as tied by Davie McPhail, Fario Fly (Black).